No one is talking about it because you can't prevent infections from spreading in crowded environments.
So there is no advantage at all having some filter on top of the train, pushing the air from top or bottom to the other direction?
I would assume that those droplet infections should become less.
Sick people touch surfaces, you touch surfaces. Then you touch your face.
I'm more sick than collegues using there cars and bikes. That is really expensive.
And there might be a moment in time where it is not a cold virus.